Reference signals are transmitted by a first communications device to allow a second communications device receiving the reference signals to make measurements of the channel, obtain synchronization, and so on, based on the received reference signals. Therefore reference signals are crucial to the operation of the communications system. However, the transmission of reference signals consumes valuable network resources, thereby increasing communications overhead. Therefore, there is a need for systems and methods for reducing the network resources consumed in transmitting reference signals, and decreasing communications overhead.